CHEMICAL STRUCTURES OF THE CORE REGIONS OF CAMPYLOBACTER-JEJUNI SEROTYPES O-1, O-4, O-23, AND O-36 LIPOPOLYSACCHARIDES

Complete structures, including the location of N-acetylneuraminic acid (Neu5Ac) residues, were assigned for the core regions of Campylobacter jejuni serotypes 0:1, 0:4, and 0:23 and 0:36 lipopolysaccharides (LPS). In continuation of earlier studies, structure determinations of liberated oligosaccharides and, where necessary, of intact LPS, were by H-1-NMR spectroscopy, Smith degradation, chromium trioxide and enzymic degradations, in conjunction With methylation studies supported by fast-atom-bombardment mass spectrometry and linkage analyses by gas chromatography/mass spectrometry. It was concluded on the basis of the following structures, in which each was linked 1-->5 to a terminal 3-deoxy-D-manno-octulosonic acid residue, that the core regions with qualititatively similar sugar compositions showed serotypic differences in one or more of their sequences, linkage types, and anometic configurations: [GRAPHICS] The outer regions of each structure carry Neu5Ac residues linked 2-->3 to available beta-D-Galp residues and show striking similarities with various glycosphingolipids of the ganglioside family. However, Neu5Ac epitopes are not apparently involved in determining serospecificity.